The present invention relates to a vacuum cleaner and, more particularly, to a method and an apparatus for operating a vacuum cleaner which is operated in the optimum condition in accordance with the state of the cleaning surface and the choking state of the cleaner.
In general vacuum cleaners, an input is set to a constant value irrespective of the state of the cleaning surface. Therefore, the suction force is too strong or too weak for the cleaning surface or an object to be cleaned, so that the optimum control which is comfortable to the user cannot be performed.
To solve this problem, such an optimum control can be realized by, for example, controlling the input and adjusting a suction amount of the cleaner in accordance with the cleaning surface. As a method of adjusting the suction amount of the cleaner, a method whereby the rotational speed of the drive motor is variably set is first considered. As a method of changing the rotational speed of the motor, there have been known a method whereby the phase is controlled using a thyristor and a method whereby the rotational speed is controlled by an inverter.
A vacuum cleaner disclosed in JP-A-60-242827 relates to the latter method. Namely, this cleaner uses a brushless motor which is driven by an inverter.
Although the motor which is driven by the inverter is disclosed in the foregoing official gazette, nothing is taught with respect to the technical subject for allowing the motor to be automatically operated in the optimum condition in accordance with the state of the cleaning surface or the choking state of the filter. In addition, means for solving this technical subject is not shown.